Multiband transport in bilayer graphene at high carrier densities

We report a multiband transport study of bilayer graphene at high carrier densities. Employing a poly(ethylene)oxide-CsClO₄ solid polymer electrolyte gate we demonstrate the filling of the high-energy subbands in bilayer graphene samples at carrier densities |n|2.4×10¹³ cm^-2. We observe a sudden increase of resistance and the onset of a second family of Shubnikov--de Haas (SdH) oscillations as these high-energy subbands are populated. From simultaneous Hall and magnetoresistance measurements, together with SdH oscillations in the multiband conduction regime, we deduce the carrier densities and mobilities for the higher-energy bands separately and find the mobilities to be at least a factor of 2 higher than those in the low-energy bands.